1) Field of the Invention
This invention relates to an oil recovery apparatus for a roll apparatus for recovering oil inside a roll mantle.
2) Description of the Related Art
Conventionally, a roll apparatus has been developed which includes a stationary support member, a roll mantle disposed around and rotated on a circumference of the support member, and a shoe supported on the support member for pressing the roll mantle in an outer circumferential direction from the inner circumference side, and is provided typically in a press apparatus or a calendar apparatus of a paper machine.
One of such conventional roll apparatus is equipped with a roll apparatus oil recovery apparatus for recovering oil supplied to the inside of the roll apparatus (refer to Japanese Patent Laid-Open (Kokai) No. HEI 10-82416). FIG. 10 shows the conventional roll apparatus oil recovery apparatus 91 and is a sectional view taken along a plane perpendicular to the roll axial direction of a roll apparatus 90.
Referring to FIG. 10, the roll apparatus 90 includes a center shaft 81, a roll mantle 82 disposed around and rotated on a circumference of the center shaft 81 in the direction indicated by an arrow mark R1 in FIG. 10, and a shoe 84 provided at an upper portion of the center shaft 81 for pressing the roll mantle 82 in an outer circumferential direction from the inner circumference side to press the roll mantle 82 against an opposed roll 83. The roll mantle 82 is driven to rotate by a driving apparatus not shown provided at an axial end portion of the roll mantle 82 while the shoe 84 is driven to move in upward and downward directions by hydraulic fluid supplied into a pressure chamber 86 through a hydraulic fluid supply pipe 85.
In the roll apparatus 90 having such a configuration as described above, oil (lubricating oil) 50 is supplied into the inside of the roll mantle 82 to form an oil film on a contact portion 87 of the shoe 84 with the inner circumferential face of the roll mantle 82 in order to allow the roll mantle 82 to rotate smoothly. However, as the roll mantle 82 rotates, the temperature of the oil 50 gradually rises by frictional heat generated by a shearing work of the oil 50 at the contact portion 87 of the shoe 84 with the inner circumferential face of the roll mantle 82, and this decreases the viscosity of the oil 50, resulting in the possibility that an appropriate oil film may not be formed and consequently the inner circumferential face of the roll mantle 82 may be damaged. Further, the decrease of the viscosity of the oil 50 reduces the life of a rubber cylinder mounted on the surface of the roll mantle 82. Therefore, in order to prevent a temperature rise of the oil 50, after the oil 50 inside the roll mantle 82 is recovered by the roll apparatus oil recovery apparatus 91 upon operation of the roll apparatus 90, the recovered oil 50 is cooled and supplied so as to circulate inside the roll mantle 82.
The conventional roll apparatus oil recovery apparatus 91 includes an oil receiver 88 provided below the contact portion 87 on the upstream side in the direction of rotation of the roll mantle 82 as seen in FIG. 10. The oil 50 entrained inside the roll mantle 82 is not admitted at the most part thereof into the contact portion 87 but flows down naturally by the force of gravity as indicated by an arrow mark R2 in FIG. 10. The oil receiver 88 recovers the oil 50 flowing down by the gravity in this manner. It is to be noted that the oil 50 recovered by the oil receiver 88 is discharged to the outside of the roll mantle 82 through pipes 89, 92 formed in the center shaft 81.
Incidentally, speedup of operation of a paper machine has proceeded in recent years, and also the speed of rotation of the roll mantle 82 has increased remarkably when compared with that in conventional paper machines. Such speedup, however, has given rise to a subject which has not heretofore been imagined.
In particular, since conventionally the speed of rotation of the roll mantle 82 is comparatively low as described hereinabove and the oil 50 flows down as it is from the contact portion 87 to a location below the contact portion 87 as indicated by an arrow mark R2 in FIG. 10 by the gravity, in order to recover the oil 50, only it is necessary to dispose the oil receiver 88 below the contact portion 87. However, when the speed of rotation of the roll mantle 82 becomes high, the oil 50 collides violently with and rebounds from the contact portion 87 as indicated by an arrow mark R2′ in FIG. 11, and reversing current in the form of oil spray is generated over a range on the upstream side in the direction of rotation of the roll mantle 82. Consequently, the amount of oil which can be recovered by the oil receiver 88 decreases significantly.
Particularly, in recent years, a multi-shoe controlled crown roll (M.C.C.R) has been developed wherein the shoe 84 is divided into a plurality of parts in the roll axial direction in the roll mantle 82 and the pressing force of each of the divided parts of the shoe 84 is controlled independently so that the outer profile of the roll mantle 82 in the axial direction can be controlled (crown control). In the M.C.C.R having such a configuration as just described, in order to control the crown profile with a high degree of accuracy, it is significant to assure a high recovery ratio of the oil 50 so that the oil 50 can be supplied always in a well-conditioned state (that is, in a state controlled to an optimum temperature for use) into the inside of the roll mantle 82. Further, in a self loading controlled crown roll (S.L.C.C.R) where upward and downward movements of the entire roll are performed by upward and downward movements of the roll mantle 82 itself, for example, when the roll mantle 82 moves upwardly, the gap between the inner face of the roll mantle 82 and the oil receiver 88 exhibits a greater distance, and this further deteriorates the recovery ratio of the oil 50.